The invention relates to a low-temperature method to crystallize a silicon-germanium film.
The relatively high temperature required to crystallize deposited semiconductor materials such as silicon and silicon-germanium alloys can have adverse effects on semiconductor devices. High temperatures can lead to unwanted diffusion of dopants, can cause peeling due to differential expansion and contraction of unlike materials during thermal cycles, and can prohibit the use of desirable conductive materials like aluminum which have low thermal tolerance. These disadvantages are particularly acute in monolithic three dimensional memory arrays, in which a memory level formed above a substrate will be exposed to the temperatures required to form additional memory levels stacked above it.
There is advantage, therefore, in lowering the temperature required to crystallize deposited semiconductor material.